61506821 has 4 divisors (see below), whose sum is σ = 63490944. Its totient is φ = 59522700.

The previous prime is 61506817. The next prime is 61506829. The reversal of 61506821 is 12860516.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 61506821 - 2² = 61506817 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61506829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 992015 + ... + 992076.

It is an arithmetic number, because the mean of its divisors is an integer number (15872736).

Almost surely, 2^61506821 is an apocalyptic number.

It is an amenable number.

61506821 is a deficient number, since it is larger than the sum of its proper divisors (1984123).

61506821 is a wasteful number, since it uses less digits than its factorization.

61506821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1984122.

The product of its (nonzero) digits is 2880, while the sum is 29.

The square root of 61506821 is about 7842.6284496972. The cubic root of 61506821 is about 394.7369310687.

The spelling of 61506821 in words is "sixty-one million, five hundred six thousand, eight hundred twenty-one".